How can i cancel my itune account

iTunes itself is free so has nothing to cancel. You can cancel an associated subscription to your Apple ID, or have your Apple ID deleted entirely.

If what you want is to cancel a subscription you have under iTunes, then follow the steps here: link-> How to cancel a subscription from Apple - Apple Support

If you don't want to us the iTunes Store then remove your payment methods and just stop using it. You cannot delete it, you would have to delete your entire Apple account.

For information relating to 'How to delete your Apple ID account', click here --> https://support.apple.com/HT208504

It's all part of your Apple account. You either just stop using the parts you do not want to use or you ask Apple to delete your entire account. Read the document to which I provided a link.